To get your offer on a foreclosed property accepted I have found it helps to:
1. Act quickly; the good buys are going very fast - sometimes within hours!
2. Fill out the contract and the additional forms required by the bank completely; they just don't have the time to chase you down to ask you question.
3. Make your offer as strong, simple and clean as possible; this is not the time to get creative, have contingencies, etc.
4. Submit your offer with a bank letter verifying proof of funds or a pre-approval letter from a recognized lending institution.
5. Be nice to the listing agent - she can really help you out!